Problem: Ben has taken 6 quizzes and his average score so far is 88. If he gets 100, a perfect score, on the remaining 3 quizzes, what will his new average be?
Solution: If he gets 100 on the remaining quizzes, the sum of his scores will be $6 \cdot 88 + 3 \cdot 100 = 828$ His overall average will then be $828 \div 9 = 92$.